Effects of antiglaucoma drugs on cellular proliferation in cultured human corneal keratocytes.

The purpose of this study was to investigate the effects of various antiglaucoma drugs, including timolol, betaxolol, carteolol, levobunolol, dipivefrin, and pilocarpine, on cellular proliferation in cultured human corneal keratocytes. Human corneal keratocytes were cultured with RPMI-1640 medium containing 10% fetal bovine serum. Antiglaucoma drugs were prepared from original concentrations to dilutions of 1/10, 1/100, and 1/1,000. After exposure to drugs for 100 minutes, cellular proliferation was estimated by [3H]thymidine uptake methodology. It was found that cellular proliferation in corneal keratocytes was inhibited by only a 1/10 dilution of various drugs including timolol, betaxolol, carteolol, levobunolol, dipivefrin, and pilocarpine. The [3H]thymidine uptake values were significantly inhibited to 63%, 18%, 87%, 68%, 55%, and 67% by a 1/10 dilution of the above drugs. However, the cellular proliferation was also significantly suppressed by 0.01 mg/mL of benzalkonium chloride preservative. It is shown that the inhibition of cellular proliferation by high concentrations of antiglaucoma drugs may result from the benzalkonium chloride preservative contained in these drugs.